Automatic telephone system.



A. H. DYSON.

I AUTOMATIG TELEPHONE SYSTEM. trunnion 3mm nov. 2a, 100".

Patented Nov. 8 1910.

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A. H. DYSON. AUTOMATIC TELEPHONE SYSTEM. LPPLIQATIDN IILHD NOV. 83,1907.

Patented Nov. 8,1910.

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A. H. yson; AUTOMATIC TELEPHONE SYSTEM. APPLIOLTION FILED NOV. 23, 1907.

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' A. H. DYSON. lUTOMATIG TELEPHONE SYSTEM. APELIOATION FILED NOV. 23,190i!- Patented Nov. 8, 1910.

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Original application filed November 13, 1906, Serial No. 343,255.Divided and this application filedNovem- UNITED STATES PATENT OFFICE.

ALFRED H. DYSON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,TO KELLOGG SjWITGHBOABD & SUPPLY COMPAIIY, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Nov. 8, 1910.

ber 22, 1907. Serial No. 403,527.

To all whom it may concern:

Be it known that I, ALFRED H. DYsoN, a citizen of the United States, andresident of Chicago, Cook county, Illinois, have invented new and usefulImprovements in Automatic Telephone Systems, of which the following is aspecification.

This ap lication is a division of my application filo; 343,255, filedNovember 13, 1906.

My invention relates to telephone systems ofthe specified characterwherein a plurality of selective switches are employed successively incompleting each connection.

In the'system WlllCll I show in the accompanying drawings, firstselector, second selector and connector switches are employed, and inaddition, switches of a fourth class which I term line selectors, thesaid line selectors being each connected to a first selector and havingthe function of temporarily associating the first selector with thecalling line by means of automatically controlled apparatus. 1

An ob ect of my invention is to provide means included in the telephonesystem for registering the number of calls made over each line, as acalling line, to which a response of the called subscriber is received.This I accomplish by associating with each line selector mechanism, aprinting magnet actuated when thecalled subscriber answers the call,together with an adjustable typeframe which may be automaticallyadjusted by the operation of theline selector in connecting to thecalling line so as to bring a type, bearing the number ofthe callingsubscriber, into operative relation to the printing magnet. v

The above, with other advantages of my improved system, will appear andbe pointed out more specifically in the detailed description of thedrawing and in the claims.

Figure 1, comprising parts 1, 2 and 3,

illustrates diagrammatically a preferred cir-.

cult arrangement; Fig. 2 is a front-view of a. master-switch; Fig. 3' isa side-view there of'; Fig. 4 is a sectional View of a line selector,showing particularly the primary magnet .and its associated mechanism;Figs. 5

and 6 show a first selector'release magnet and associated mechanism;Figs. 7 "and 8 show top views of an over-run and primary off-normalswitch, respectively;Figs. 9, 10,

and 11 are respectively left, front and right elevations of a lineselector. Figs. and 14: show similar elevations of a connec; tor. Fig.15 is a top-view of the registering mechanism of my invention.

Referring first to Fig. 1, the system there illustrated may beconsidered as aten thousand line system. Assumingsuch to be the case,each subscribers line such as those' of substationsA and B, extends tothe exchange and is there provided with its; individual passive multipleline contacts 20, 22 and 2ft appearing with those of ninety-nine otherlines in the contact banks of ten line selec:

tors such as D. Inasmuch as ten. thousand lines are assumed, there willhave to be in all one hundred such groups of lines, each with its tenline selectors, making a total of one I thousand such selectors. Eachsuch line sel'ectorhas permanent conne'ctionlwith a particular firstselector suchas E, which is antomatically brought under thetcontrol ofcurrents to be sent over the calling line by the operation of the lineselector D. The first selector by its adjustable wipers, gives thecalling subscriber access to one hundred second selectors, there beingten of. these representing each one thousand lines of the exchange.Gontacts of the second selector engaged by the first selectors, are, o;tcourse, multipled in the usual manner, to a large number of firstselector contact banks and would ordinarily be multipled one hundredtimes or to one hundred such banks. j

Responsive to currents transmitted over the calling line by thesubscriber, the first selector is caused to select the group of secondselectors corresponding to the one thousands digit of the called number;the first selector then'automatically selects the-first vided in tengroups of ten switches each, the,

switches of each group being adapted to select out any particular lineof a onehundred line group of subscribers to which the switches of thegroup are assigned. The contact terminals of the connectors are, of

course, multipled alarge number, of times and would ordinarily emultipled in the present 5 stem one hundred times or to each second soector of a one thousand line group.

Tlie second selector operating responsive to I currents controlled atthe calling substation, selects the group bf connectors desired, andthen the idle connector, thereby placing it at under the] control of thecalling substation. Tl. co lube-tor, by its wipers, has access to,contact forming multiple terminals of subiscriber lines forming a onehundred line group, said. contacts being multiplied ten times to appearin the contact banks of ten connectors. i In a1 ordinarily busy exchangeof ten thousand lines, one thousand line selectors ,with their onethousand first selectors, one ;thousapd"second selectors, and onethousand lconnec .ors, would be adequate to handle the business of theexchange.

As above indicated, line selector D by ,1 means? of its wipers hasaccess to one hun- 26 dred sets'of multiple contacts 20, 22 and 24forming terminals .01 a group of one-hun dred subscribers lines. Thecontacts'of these lines are preferably arranged in ten groups of tencontact sets each, the motion of the 25 wipers of switch D being firstin a. primary direction in on: plane to select a group of contacts, andthen ina secondary direction in another plane to select the calling line0 the group. Each group of ten lines therefore, has a common or groupcontact 26 controlled by a common relay 18, which contact the wiper 27engages. The said wiper 27 controls the primary movement of the switchD, the line wipers-21, 23 and 25 moving 5 along with the said wiper 27.When the wiper 27 reaches a group contact 26 belonging to a group oflines among which a call ing line is included, the primary movement ofall the wipers is arrested and the line wipe-rs 21, 23 and 25 theninitiate their secondarymovemenls to select the individual contacts 20,22 and 24 of the calling line, wiper 27 remaining quiescent at this timeand not partaking of the secondary move- 11 ment.

As before stated, each group of one hundred calling lines has associatedwith it ten line selectors D, so that, the contacts 20, 22 and 24 ofeach line and the group contact 26 of each group is mult-iplecl tentimes, once to each such line selector bank. When the,

calling-subscriber removes his receiveryhe causes a line selectortostartinto operation to seek out his lineand thereby 'connect the firstselector with said line.

through the agency of the master-switch C to whose relay 28 each callingline is enabled to Lausmit current by means of the switch gontacts ofits line relay 9. The said masterwitch when operated at the initiationof a call as above indicated, causes an idle line selector to start itsoperation. The line selector then re-acts'upon the master-switch in suchmanner that its wip rs 30-34 move 5 away from the switch contacts 3135of the This is effected.

line selector which they start, and then keep up an independentprogressive movement via terminals 3 '35 of busyline selectors untilthey reach terminals of an idle one, when the said wipers come to rest.The detailed relation of the different parts to one another will be bestunderstood through the narrative of operation.

Assuming that subscriber A is to be connected with-subscriber B whosetelephone number will be assumed to be 3456, subscriber A, first removeshis receiver thereby completing a conductive bridge of limbs P and S bythe usual elevation of the hook lever. Relay 9 from ground therethrough,normal armature contact 14 over limb P through hook lever andtransmitter at station A, limb S, normal armature contact 16, to batteryB. Armature 10 is thereby attracted to engage its switch contact,(immediately thereafter breaking the normalcontact' of said. switchcontact whereby substation control of relay 9 is removed) to complete alocking circuit for" said relay established from ground therethrough,contact 10, contact 17, relay 18, to battery. Relay 18 attracts itsarmature to remove group contact 26 at each line selector of the I ten.Armature 11 disengages its normal contact to remove ground from each ofthe individual private contacts 20 of the line at the ten lineselectors, and the. said armature engages its alternate contactoperatively connecting relay 12 with the contacts 20. The lower armatureof relay 9 engaging its contact, completes a circuit from ground throughresistance l9,'the left-hand winding of tery, causing said'relay toattract/its armature. and complete an energizing circuit of relay 29which latter attracts Its armature and causes a flow of current asfollows: from ground at its armature through con tacts 3031, contact 40,at an idle line solector D (wiper 30 when resting always enhereafterexplained) through relay 37 of said line selector to battery. Relay 37attracts its upper armature and closes circuit from ground throughresistance 36, righthand winding of relay 28 to battery, whereby thearmature of relay 28 is allowed to fall back, because the said relayis'difierentially wound, and resistances 36 and 19 are equal. It isapparent that relay 29-is thereon. immediately armature retracted.Armature 39 of relay 37 is attracted closing circuit through vibratoryprimary magnet PM, which becoming energized,.'advances wiper 27 toengage the first group contact 26, Wipers 2 1, 23 and 25 moving oppositethe contacts of the first group but not engaging any contacts. Relay 37has attracted its armature 38 and; if

ground from the multiple' master-switch relay '28 to batgages contact 31of an idle line select-or as,

deenergizedand its is energized by current/ v '27'to engage the thefirst group contact 26 engaged is in its normal condition, no line inthe group then calling, the said contact will be grounded at thearmature of grou ing circuit is completec for relay 37 from ba terythrough said relay, attracted armature 38, contact 27-26 to ground viaarmature of the first group relay 18. As armature 39 thus continues PMis, on the retraction ott its vibratory armature, again energized andmoves wiper second group contact. If this contact has its normal groundat the second group relay 18, relay 37 will continue energized and thepreceding process is repeated; wiper 27 engaging the third group contact26; and so on until the group contact of a calling line, that ofsubscriber A, is found whose ground hasbeen removed by the previouslydescribed operation of relay 18. No locking circuit for relay 3? is tact26 of the the original energizing circuit of relay 37.

then completed and its armatures are'retracted, the armature 39preventing further operation of primary magnet PM Whereby wiper 27 restsengaging group conten line group including line A, while line wipers 21,23 and 25 have moved along with wiper 27 to such a posi tion that theyare ad acent to the group of contacts including a line contact set ofsubscriber A. a

On the first primary movement of the wipers, contacts 10l1--42 of theprimary ofl -normal switch P.O.Sw were shifted to their alternatepositions, contact 40 opening Contact 41 completes a circuit fromground, through contacts 34, relay 32 to battery B causing relay 32 toattract its armature whereby circuit is completed for magnet 33 of themaster-switch, which, by its energization, advances wipers 30 and 34L astep to engage contacts 3135, respectively, of thenext line selector, itbeing understood that the said wipers have in front of them ten contacts31 and ten contacts 35, belonging in pairs to ten line selectors. If thecontact 35 now engaged by wiper 34- belongs to a busy line selector,that is, one in which spring 41 has been shifted, relay 32 will continueenergized by current from this second line selector-via its shiftedspring 41 magnet 33 Will step wipers FED-34 one step farther, when theabove process will he rc peated'if that line selector is in use, and soon until Wiper 3% engages contact 35 of an idle line selector, when itscontact 41 will be as shown at D, namely, on open circuit whereuponrelay 32 will become dci nergizcd preventing further operation of magnet33, and wipers 30 and will remain on the contacts of an idle lineselector waiting for another call to come in.

Returning now to primary otflnormal switch contact 42, its shiftingoperatively relay 18, and lock cuit is completed from ground attracted,.magnet movi'ng wipers 212325 to 34 of the master-switch connects theWinding of relay 48 with the normal contact of the upper armature ofrelay 37, so that on the denergization of said-relay occurring as beforedescribed, cirat said upper armature, through contact -12, normalcontact 1-5, relay 18 to battery B.- Relay 4:8 is there by energized toinitiate the secondary more ment-ot wipers 21, 23 and 25 by means of itsarmature 51 which closes circuit from battery through secondary magnetSM, armature contact 51, tov ground through alternate contact of switchspring 46, springs et(it7 of the release switch RS112 having beenpreviously shifted on the first energization of primary magnet PM.Wipers 21-23 25 engage contacts 2O -2224; respectively, belonging to thefirst line of the group. When it is at normal, that is, when the sulrscriber is not making a call, its multiple con tact 20 will be groundedby way of the normal contacts 11 and 15 of its relays 9 and 12; hence,armature -50 of relay 48 being at this time attracted, a locking circuitwill be closed from grounded contact 20, Wiper 21, attracted armature50, relay 18 to battery and armature 51 continuing attracted, secondarymagnet SM, will, on the retraction.

of its armature, become agaln energized engage contacts 2O2 2'24t ofthe. second line of the group. If this line is not calling, its contact20 will be grounded and relay 48 will continue to be locked as beforedescribed, a third de'energization and energizatioh of secondary magnetSM resulting, advancing the wipers the third secondary, movement, and soon until contact 20 of the line of subscriber A is reached, whichcontact on account of the attracted condition of arma.- ture 11 of relay9, is ling-rounded, whereby locking circuit of relay 48 is destroyed,its armature retracted, opening circuit of secondary magnet SM andpreventing further movement of wipers 212325 which remain in engagementwith the multiple contacts of the calling line. 52 were held attractedduring the secondary movement of the wipers in order that wipers 23 and25, which were then wiping over line contacts of the various lines,might be insulated so that no disturbance of existing conversationscould oc'cur. Upon the deenergization of the relay 48, they will ofcourse be retracted to extend wipers 2325 to connection with thecircuits of the first selector E. Contact 50, upon the dciinergizationof the relay, falling back to its normal grounded contact, completes acircuit from grounded contact 50, contnct 21-20 and" alternate contact11, cut-olfirelay 12to battery B, energizing the saidgelay 12 which, bythe operation of itsar'niature 13, completes a locking circ, "tfor'its'elf to the same ground at content While armature Armatures 49and 14 completes a circuit from limb P through to wiper 23. Armature- 15removes the ground from the normal contact of armature 11 of relay 9,thereby preventing a permanent locking of relay 12 which would other-Wise occur when 'a, connector engaged contact'6 of the line. Armature16in its-operation, opens the normal connection of battery 7 B to limb Sand completes the circuit of said line limb through to wiper 25, Whilearmature 17 opens the previously extending series circuit through relays9 and 18, cansing the denergization of both of them and the retractionof'their armatures, that of ,relay 18 again grounding group contact 26.

Since ground at armature 50 of relay 48 is now connected to the privatecontact 20 individual to the line, its multiples are nonselectable byany other line selector.

The secondary off-normal switch S.O.Sw contacts 4445 were shifted at thefirst energization of the secondary magnet SM, spring 45 interruptingthe original energizing circuit for relay 48; while spring 44 interruptsa neutralizing circuit including resistance 36 hereafter described, andsaid spring 45, by engaging its alternate contact, operativelyassociates relay 48 with the normal contact of release switchspring 46for use in the restoration of the line selector, as

hereafter described.

It will be observed that upon the retrac tion of the armature of relay37, which in its attracted position originally completed theneutralizing circuit for rela 28, a new path for continuing such neutraization had been completed by the shifting of switch spring 46occurringon the first actuation of primary magnet PM, the newneutralizing circuit extending from the ground of said switch spring 46,its alternate contact, no'rmal contact of switch spring 44, and re-'sistance 36. This circuit is of course broken on the first energizationof secondary magnet SM by tlie shifting of spring 44, but before thatoccurred, a thirdicircuit was completed from ground at switch spring 46,

I ing of'relay 28. Thus, it will be observed thiiylikglay windingscontinuing until selecits alternate contact, attracted armature 51 ofrelay 48 and resistance 36. This last circuit "continued until thedeenergization of relay 48, when the circuit of resistance 36 in theright-hand winding of relay 28 is opened at contact 51; butsimultaneously with the opening of this circuit, relay 12 was operatedand relay 9 denergized', the retraction of the lower armature of thelatter opening the circuit through the left-hand wind that fromtl1e'ti1ne',tl1e line selector starts, armature of relay 28 willremainretracted as far as line A and sw itch D are concerned, first because ofthe neutralized condition of tion "of the line, and thereafter becauseof the} practicallysimultaneous opening of the neutralizing circuits ofits windings. Thus an untoward attraction. of its armature is preventedwhich, should it occur or exist after wipers 30 and 34 have reachedcontacts 3l35 of an idle line selector, would cause the initialoperation of saidselector to no avail, as there would be no calling linefor it to make connection with.

The relation of the master-switch to the line selectors and the callinglines which it serves, is such that as many line selectors will bestarted to seek out calling lines as therefore, the armature of relay 28will continue attracted, and as soon as the wipers 30 and 34 reachcontacts 31 and 35 of the next idle line selector, this switch will alsobe in circuitwith the right-hand winding of started; there will. then betwo windings 86 relay 28, but there being three windings in circuit withthe left-hand winding, its armature will continue attracted, and whenwipers 30 and 34 reach the third idle line selector, this one will alsobe started in search of the third line. As soon as this switch starts,however, a third winding 36 will be included in circuit with. therighthand winding of relay 28. The three windings 36 will effectivelyneutralize the three windings 19, the armature of relay 28 will beretracted, and when wipers 3034 engage contacts of a fourth idle lineselector, this switch will not be started.

One of the rarely occurring. instances above referred to where more thanthe required number of line selectors will be started may be imagined asfollows: Suppose that the positions of wipers 30 and 34 of themaster-switch are such that. the first and second steps will cause themto engage contacts of idle line selectors. Let it be also supposed thata call comes in from a line whose individual contacts are the 9thcontact sets of the fifth rows in the line selector banks, and that acall simultaneously comes in from a line whose individual contacts arelocated in the seventh group or row of cont'acts. In such cases, a lineselector D'would start, Its starting would throw wipers 30-34 upon thecontacts of the next line selector; relay 28 continuing energized owingto the inclusion of two windings 19, one

for each calling line, would cause this second fit) line selector toinstantly start, and the two ine electors would be simultancously perthefirst one reached the ninth contacts of.

the said group, and as a result, the wipers of the second line selectorwould begin wiping along the fifth row in Search of the line contacts ofthe calling line. But the first line selector beingtwo steps in advancewould reach the contacts'of the calling line first and render themunselectable so that the second line selector would continue,

passing the said contacts to be released when it reached the end of thegroup by means of the switch spring 43, so arranged in the switchmechanism as to be shift-ed when the line selector is over-run on itssecondary movement. In' the meantime, wipers 30-34 have been ,moved to.engage the contacts of the third line selecton' This line selector hasnot been started since the armature of relay 28 was retracted. As soonhowever, as the second line'selector is released, its winding 36 isremoved from circuit of relay 28 and winding 19of the sec ond callingline is therefore again effective to attract the armature of relay 28and causes the operation of the third line selector, which proceeds inits orderly operation to select the second calling line; We thus havethree line selectors operating to connect lirst selectors with the two.calling lines. Taking into consideration the various taci: torsnecessary for the occurrence of the above described OpBlatl0I1,1i3 1sapparent that even in the case of callssimultaneously coming in from asingle group ofone hundred lines to its master-switch; the above'operation will very rarely occur.

The amount of time required for the operation of the line selector toconnect'with the calling line is exceedingly small relquin .ing, (aswill be more fully understood, when the mechanical features of theswitches are described hereinafter) a maximum thirty step-l') v-stepmovements underthe most-untavorable condition, the switch'eisb'cing ofsuch cliaractcr that tl'iis-ninnber of steps can be performed in lessthan one second of time.

Subscriber A desiring his to be connected with the line 3456, iiowttperates C2lll-' ing device to transmit. three impulses of currcnt, byrotating the said. device cloclcwise until three of its insulated teethhave passed below spring 3 and then releasing it Where on its associatedspring turns the dial in the opposite direction, the three insulatedteeth each causing spring 3 to engage and disengage its contact once.With the return of the dial to norma its insulated tooth at the extremeleft causes sp,ing. 2 to engage its associated contact a single time,thereb sending one impulse of current over limb 'but not until the lasttooth at the right has sent the last impulse over limb P.

While the-dial is at any other than at.

normal. position, the pin shown thereon is 1 brought toisuch positionthat tension is removed from spring 4.- which then disengages itsassociated contact temporarily conductively disuniting the two linelimbs P and S at that point in order that impulses may be sent over theline limbs separately. The operation of the dial as described, sendsthree impulses of current from ground at the substation through spring 3and its contact, over. limb P of the line, through itttracted armature14, contact 2223, ar-

mature 49, contact 54 at switch E, upper armature of relay 73, contact55, through the winding of primary relay PR to battery causingtheenergizations and deenergizations of said relay whose thriceattracted armature, causes three impulses to flow from ground througharmature spring 57, and its alternate-contact, contact 58, primarymagnet PM ,-.to battery. The three resulting energizatilons of PM movethe first selector switch Wipers 59-60-61 to positions'adjacent to thethird group of second selector contacts, terminals of second selectorsbelonging to the third thousand lines including those from 3,000., to3,999. With the first primarymovement of the wipers, the primaryoff-normal switch P.O.Sw contact, and the release switch RS'w contact,are

shifted to their alternate positions preparatory to the energizationofthe secondary magnet SM'. 4

lV'th the return of the dial to normal,- an impulse flows irom groundat. thersubstw tion through 3 ring,2 and its contact over limb S of theine, through attracted arn ature 1.6, contact .24-25', contact 52,through contact 62 at switch E, lower armatureiof relay 7 3, contact-64,winding of secondary relay-SR, to battery, causing the attraction andrelease of said relays armature and. a flow of cflrrent-from groundthrough spring 65 and its alternate contact, contact 66 and busy relayBR, to battery. Contacts 6770 are attracted to disconnect wipers 6061-from battery while wiping over. contacts of busy second selectors;armature 68 is at treated to close circuit from ground through theprimary oil-normal switch P.O.Sw', the alternate contact of the releaseswitch R310, alternate contact 68, secondary magnet SM to batteryv Thesecondary magnet having a vibratory circuit, attracts and releases itsarmature, the operation beingeffective to move wipers 59 .606l intoengagement with contacts 868788 of the first second selector of thegroup. With the first secondary movement of the wi ers, the secondaryofi' -nor1 a1 switch .O.Sw contacts 58-66 are shr ted to dperativelydisconnect the windings of the primary magnet PM and of the busy rela'yBR from switch springs 57 and 65, respectively. It, the second selectormentioned is idle, it will be in the condition shown in Fig. 1. Contact86 being on open circuit, busy relay BR becomes denergized, armature 68opens the circuit of magnet SM, and the wipers rest in engagement withthe contacts of the first second selector; armature 67-70 by theirretraction render the said second selector re sponsive to current to betransmitted by.

relays PR and SR.

Armature 68 in engaging its normal contact, places direct ground throughthe primary oft-normal switch 1 .0.8112 and release switch contacts,normal contact 68, right-hand armature ofRM and wiper 59/ upon contact86 of the second selector and its multiples to render the said secondse- K .lector busy. 3 0

It will therefore, result, that should the wipers of another first"selector now be brought to engage multiples of contacts 8687-88 ofthe'first second selector switch F, busy relay,BR of this other firstselector then energized will have its circuitv continued in ,thiscondition by current flowing from grounded 'contact- 86 .to its multipleengaged, the right armature contact of RM, through attracted armature69, of its busy relay BR, through said relay. to 'battery. The relaywi'l therefore, continue as be energized. Secondary magnet SM by theretraction of its armature will have its circuit closed and becomeenergized and deenergized a secondtime, movingthe wipers 59,60 61 toengage the contacts of the second second selector of the grouo. If thisbe in use,'another lockin circuit fdr busy relay BR will be est'ablised'as the preceding one is broken; SM advances.thejvipers a third step,and soon until contacts of an idle second selector are reached, whenowing to the insulated-condition of its contact 86, the deenergizing ofBB ensues, preventing further operation of 'SM, and the wipers come tcr'res t.

Returning to the connection being established, subscriber A'now operatesdial 1 to transmit four, impulses of current through relay PR'UVQ-l theabove traced path, which said relay is operated four times transmittingfour current impulses from ground through alternate contact 57, normalcon tact 67, contacts .60-87, normal contact 89,-

normul contact 91, primary magzet PM to battery, causing fou:-energizations of the said primary magnet. The said magnet thereby moveswipers 9f?!.l l---95' of the second selector adjacent to a group ofcontacts,

terminals of connectors belonging to the fourth one hundred'group ofsubscribers lines of the third thousand, 'this including lines from3,400 to 3,499. With the first movement of the wipers, the primaryolinorinal switch springs P.O.Sw are shifted to their alternatepositions and also the spring of the release switch RS40 VVi'th thereturn of the dial to normal, a single impulse flows from ground at thesubstation through relay SR over the before traced path, said relaybeing 'energized and .deenergized to transmit a current impulse fromground through spring 65 and its alternate contact, through normalcontact 70, contact 6l88, contact 90, busy relay BR to'battery,energizing the said relay. Its upper. armature 'and armature 98 placewipers 94: and ,95 on open circuit, while armature 96 completes circuitfrom ground atthe primary off-normal switch P.().Sw='

through the alternate release switch RS'w contact, attracted armature 96and the winding of the secondary magnet 3M to battery, causing the'energization of said magnet which is eitective to cause wipers esoiresto engage contacts 99-100- 101 of the first connector of the selectedgroup.

If contact 99 belongs to an idle connector, 1t

will be on open circuit as shown at Gun Fig 1. No locking circuit forrelay BB will result from the attraction of armature 97,

back, the upper armature and" armature 98, ope-ratiyely connecting thetircuits of the connector with relays Plit'and SR, rendering the connecor controllable from substation A, While armature 96 opens the circuitand the armature of said relay fallsof secondary magnet SM leaving thewipers in engageh'ient with the terminals of the first connector of thegroup, and, by the engagement of its alternate contact, said arm ature96 places dead ground from the primary ottnormal switch springs,alternate contact of release switch 'RSw normal contact '96, normalcontact of the right armature of release magnet RM contact 93.--99 uponthe multiples of the said con}; tact 99 appearing at the other seconds.e lector banks, so that if another second-so lector F. has its wiper93 brought to engagement with a multiple of contact 99, its relay BBwill be locked by current from grounded contact 99'viaalternate contact97; secondary magnet SM then advances the wipers to engage contacts.terminals of the If this consecond connector of the group. I tact 99belongs to an idle connector, the second selector will stop itssecondary movement and the contact 99 will be rendered busy as describedin connection with the second selector I so that a third s cond -j 5adjustment they are lector seeking a. connector in the same groupwillselect the third connector of a group, and so on.

With the first secondary movement of the wipers 93, 94, 95 springs,89-90 of the secondary off-normal switch ed to opcratively disconnectprimary magnet PM and busy relay BB from relays PR and SR. Subscriber Anow operates dial .1-0 1 transmitting five impulses ofcurrent fromground at the substation through relay PR, causing. five actuationsthereof, which are effective to transmit five impulses of current I fromground contacts 67, 60-87, 94-400, normal contact 102, contact 103,through primary magnet PM at the connector G to battery. Five resultingactuations of said magnet are effective to move Wipers 105'106-107topositions adjacent to a group of ten contacfisets in .their banks,forming terminals of the fifth group of the one hundred lines which theconnector serves, namely: terminals of lines from to 3459 inclusive,followed by terminals-of line 3450, it being understood that zero isrepresented by ten current impulses. With the first primary movement ofthe wipers, primary off-normal switch spring 110-Sin is shifted tooperatively connect contact 99, via-normal contact 122, with the windingof ,the release magnet RM to place the same under control of the callingsubscriber, as will be hereinafter more fully'explained.

With the return of dial 1 -to normal, at single impulse is transmittedafter the last of the five preceding ones fr'om ground over limb Sthrough relay SR, traversing a-be fore traced path, actuatin relaySR asingle time, whose armature is efi'ective to transmit a single currentimpulse as follows: from ground, contacts 65, 70, 61, S8, 98, 95, 101,normal contact 108, 'net RM through secondary magnet to battery. Thesecondary magnet SlVP is (5 thereby actuated a single time moving wipers105, 106, 107. one step nearer the selected contact group, it beingunderstood that the normal positions of the wipers of a connector aresuch that after any primary two steps distant from the first contacts ofthe group selected. lVith the first secondary movement of the w-i ers,springs 102]08 of the secondary 0 normal switch 3.0.820" are shifted;102, 'to enjilage its alternate contact, while 108 is shiftedtonlysufiiciently to disengage its normal contact; a second step of thewipers being required to shift it sufliciently to on gage its alternatecontact. This arrangement of spring 108 is for the following pur hose:to prevent an otherwise possible premature operation of test relay TltWlUCll would occur were spring 108 completely shifted to engage itsalternate contact before secondary relay SR had its armature resir,

$11810 are shift-' sequent wipers 106107 which through alternate contact57,

spring 57,

lower armature of magthe impulse transmitted by tracted; groundedalternate SR through contact 108, lower armature ofrelay 109, left-handWinding of relay TR to 1 battery, which wouldcause the energiZation anddeiinergization of relay TR and the con f 111 of the test switch. wouldcause ringing gized to include generator in circuit with: shouldproperly be; on open circuit during the other seconeiiary movements toconnect with the called line. Subscriber A now operates dial 1 totransmit six current impulses from ground at the substation throughprimary relay PR, causing six actuations thereof and six currentimpulses to be transmitted from ground via over the before traced path,con tact 102, the impulses then passing via alternate contact 102,normal switch contact of. upper armature of relay l09,'lower armature ofmagnet RM secondary magnet SM to The first resulting actuation ofsecondary magnet SM moves wipers 105- 10('3 107, now on their normalopen circuits, to engage contacts 6, 7-and 8 of the first line of thegroup, or line 3451, and with this movement, the complete shifting ofsecondary off-normal switch spring 108 is accomphshed; The succeedingfive actuati'bns of 8M are effective only to move wipers 105- 106107successive steps, the sixth actua tion causing them to engage contacts67+ 8, multiple terminals of the called line 3456 belonging tosubscriber B. After the trans mission of the last of the six impulses, asingle inipulse is, in the usual manner, caused to flow from ground atthe substation over limb Slto secondary relay SR Whose actuationtransmits an impulse from ground through contact 65 over the beforetraced path to contact108', thence via its alternate contact and thenormal contact of the lower 1 armature a relay 109 through theleft-hand.

winding of test relay TR, to battery, causing the said relay to attractits, armatures. Let it be first assumed that the called line B isidle,in which case as shown, contact 6 is connected to battery B through thewinding of cut otl relay 12, there being no ground connection to thesaid contact except through battery; The attraction of the right-handarmature of test relay TR connected its right-hand winding from batterythrough said attracted armature, normal contact 10%, normal contact 110,wiper 105, to contact 6, but since this contact is already connected tobattery, upon the cessation of secondary relay shifting of switchsprings 110 and 5 The shifting of 111 relay 112 to be ener- SR, testrclay'TR is detinergized, its armatures falling back, this beingeffected to shift springs 110 and 111 of the test switch Ta m. Theshifting of spring 110 connects groulnl to wiper 105, contact 0 anditsmultiples, completing circuit through cut-off "relay 12 of calledline B to battery. The resulting attraction of armatures 14 and 16 v+6ompletes the circuit over limbs P and S of the called-for line tocontacts 7'and 8. That of 14 also disconnects line relay 9 from limb 1The shifting of test swltch spring 20 111, completes circuit throughrelay 109 from ground, spring 111, contact 115, ringingrelay 112, tobattery B traction of the armatures of relay 109, a circuit is completedfrom ground through nor- 2 mal contact of the lower armature of relay1%7, normal contact 119, attracted armature o relay 109, alternatecontact 102, cont-acts 10094, 87-60, contact 67, normal contact 57,contact 71, magnet 73 to battery, causing the energization of saidmagnet 7 3 whose attracted armatures complete a bridge of battery Bin'the line of subscriber A from ground through upper windings of relays74: and 75, attracted upper armature of relay 5 73, contact 54i,'to theleft over the heavily marked conductor, to limb P through theltransmitter at the substation, returning over llimb S and the otherheavily marked coni :ductor, contact 62, attracted lower armature 49 bfrelay 73, lower windings of relays 75 and 7 1 to battery. Differentiallyconnected rel ay 7 1 ,is not energized, the flow in'its two windingsbeing equal but cumulatively connected relay 75 attracts its a-rmaturesof which 56 and 63 complete parallel paths from ground and battery tolimbs P and S respectively, while contacts and 64; disconnect relays PRand SR- from the talking circuit. 3

Having explained the effect of the shifting of spring 111 at G withrespect to the first selector, I will now describe its effect withrespect to the called line. Its shifting energizesringing relay 112 overa before traced 55 circuit and the attracted armatures of said relaycause alternating current to flow from generator G upper armature ofrelay 1'12, contact 1067, alternate contact 14, limb P of the line of B,normal hook switch contact,

bell and condenser, limb S, alternate contact 16, contact 18, 107,attracted lower armature of relay, 112, lower winding of relay 113through \battery B The interrupter I is W provided in the circuit ofgenerator G? so arranged {as to periodically connect the said line, inthe well-known manner.

On the resulting at-fl generator in and out of circuit; ith said it willbe observed however, that the brushes of I are so arranged that at alltimes during the ringing, ground is connected to limb P of the rung lineeither through generator or the grounded brush of the interrupter. Y

It should be observed that the character of relay 113 is such that theflow of generator current through the substation condenser does notactuate the relay. As soon, how ever, as the called subscriber answersthe call by" removing his receiver, the substation hook lever engagesits alternate contact completing a conductively continuous circuit fromground through generator G or interrupter 1 as the case may be, to limbP over the before traced path for ringing current, the alternate contactof the hook lever and. through the transmitter, returning over thelimblS and thence overthe before traced path and the lower winding ofrelay 113 to battery 13". Current flowing over this conductive circuit,energizes relay 113 whose attracted armature 114: first completes, byengaging spring 115, a locking circ'uit'including serially the alreadyenergized relay 109 and the upper winding of relay 113 causing 'bot-hrelays to remain energized, the said armature. immediately thereafterbreaking the normal contact 115, thereby efii'ecting the dee'nerizationof ringing relay 112 and the immediate exclusion of generator G fromconnection with the called line. The attraction of the lower armatureand armature 116 of relay 113 bridges relay 117 across the called-forline, which relay is immediately energized by current flowing over saidline. The lower armature of relay 117 disengages its normal contactwhereby the before traced circuit through magnet 73 at E is interruptedand the said magnet is deenergized, the consequent retraction of itsarmature shifting springs 5%71 and 62-72 to their alternate positions.The deenergization of 73 does not effect the continued energizationafter breaking the normal contacts of said springs reverses theconnections of battery B to the calling line, causing a reverse flow ofcurrent thereover through the substation. This reversal of directcurrent over the calling line occurrin when the called subscriberanswers the call, may profitably be employed for various purposcs,.asfor instance, in connection with the polarized structure shown in Fig. 5of my United States Letters Patent. #830 ,('53, issued September 11,1906. The attraction of armature. T7 encrgizes printing magnet 77 whichthereupon by the aid of its associated mechanism prints the nulnber ofthe calling line recording a completed call against it.

Returning now to relay llT at. (l. having explained the et'l'ect ot thelower armature. of said relay in disengaging its normal contact, it willbe observed that the said armature engaging its alternate contact,completes a. circuit from ground through relay 118, said relay 118 bythe attraction of armature 121. establishing a locking circuit foritself through switch spring 110 ol' the test switch-'lhw to ground.Armature 11$) com pletes the talking circuit to wiper 106; armature 120,closes a break in the circuit of release magnet RM", while armature 122in leaving its normal contact removes the previously existing control ofrelease magnet RM from the calling substation, and by engaging itsalternate contact. places an ilulependcnt groundupon contact 99 and itsmultiples, so that the connector is now rendered unselectable by anyother second selector until both subscribers have replaced theirreceivers, which will be hereafter more fully explained. The twosubscribers A and B are now in conversation. circuit being traced fromsubstation A to substation It by m *ans ot the hca vily markedconductors and condensers 81-82 through the exchange, talking batterybeing supplied to the calling line through the impedances of relays74--75 and to the called line through the impedances of relay 17 at theconnector.

Vhen the subscribers have finished their conversation, they replacetheir receivers upon the hook levers. the act of subscriber l in sodoing restores the connector (i to normal. while the act ot subscriberin so doing. restores line selector 1 tirst selector ti and secondselector F to normal. The purpose of dividing the control o't-therelease in this manner may be stated as tollows: lrimarily. it is o'lcourse dc:-:irable that each subscriber b able to tree his line from anyswitch connected to it lest. should one subscriber have sole control ofthe re lease. he might by carelessly or maliciously failing to hang uphis receiver, hold the other line busy preventing its use. The controlof the release of the connector by the calling subscriber, after thecalled sulr scriber has answered. is preferably pre vented because wereit allowed, when the calling subscriber replaced his receiver firstthereby causing wipers 1(l5 l06- -107 of connector (1 to leave contacts('-7 -8 of the called line,,it would result that upon the to cause therelease at the 'lhe replacing of the opening circuit through breaking ofcontact 105(, outwit relay 12 of the called line would be det nergizedand upon the retraction of its armatures, the substation receiver at Bbeing otf the hook, relay 9 of the called line would be energizedcausing the selection of the line by one of the associated lineselectors. The called subscriber B, would of course be replacing hisreceiver at about this time, and if he replaced it before the lineselector co1'n] )letcd the selection, the said selector would come torest in connection with the line, and so remain rendering the line busyagainst incoming calls, etc.

\l'ere the called subscriber enabled, 7 replacing the receiver, torestore all of the switches used in the connection including the lineselector connected to the calling line. the inconvenience. pointed outin the preceding mragraph would be duplicated.

In consequence ot the division of the release operations indicated, thearmature 122 and its grounded alternate contact is provided whichetiective as subscriber answers, to place a second ground upon contact99 ot' the connector 'and its multiples, in addition to-the groundalready placed upon said contacts by the operation of the secondselector lest, should the calling subscrili er release the secondselector (thereby opening contact 99-93 before the calledfor subscriberB replaces his receiver), another line selector F in connection withanother calling line. seeking an idle connector in the same group. mightselect the connector already. connected to called line B. It will hethus seen that although subscriber B has independent control. of therestoration of switch and sn'bscriberA has independent control of therelease of the other switches, D. E and F,' the cooperation of both isrequired to remove the busy potential from the private contact 99 ot'the connector.

I will now trace in detail the release operation occurring when thesubscribers replace their receivers. Vl'hcn subscriber B does so. theoperation oi arm 5 of the hook lever upon its associated contactsprings, momentarily grounds limbs l and 5' in the usual manner. butthis operation is not used called substation. receiver causes the itsalternate contact relay 117. held energized by current over the lineduring eonversation. The upper armature of relay 117 then falls back.and completes a circuit through release magnet RM from ground throughcontact. 120 of relay 11S, upper armature contact 01 relay 117 tobattery. (it-- fecting the encrgization ot' the release magnet whosearlnature is thus attracted. shifts the switch springs110111tonormalfopei'iing the circuit of relays 109, 113 and 11% causingtheir denergizations. The deenerbook lever to disengage soon as acalled. I

gization of relay 11S opened the circuit of the release magnet RM whosearmature thereupon is retracted and wipers l05106- 107 allowed to returnto normal, their restoration causing, on its completion, the shifting tonormal of the primary oft-normal switch 1 .0.310 the secondaryoil-normal switch springs SOS m being restored at the time thewipers'have been restored as to their secondary movements. When thecalling subscriber replaces his receiver, arm 5 temporarily groundslimbs P and S of the line, the grounding of limb S short-circuit ing theupper winding of differential release relay 74, and, current continuingthrough the lower winding of said relay to ground at the substation, itsarmatureis attracted to complete circuit through release magnet RM atswitch D; from ground, at tracted armature ofrelay T l, release magnetRM of switch, E to battery. The attracted right-hand armature of releasemagnet RM closes circuit through release mag net RM at second selector'E from ground through the shifted primary oft normal switchP.O.Swcontact, contact 86 59, at tracted armature of RM to battery.'lfhe release magnets of all the switches D, E and F, are now energizedand their energizations shift to normal the various release switchesRSw, RSw and RS10 the shifting of said switches causing respectively theenergizations of relays 48, BR and whereby the Wipers of the variousswitches are dis connected from battery and so held during the releaseof the switches. In the restoration of the hook lever at substation A,arm '5 passing from the top of its associated contact spring, removesground from the two limbs of the line and the armature of relay 74returns to normal deenergizing release magnets 11M and RM, thedeenergization of RM opening thecircuit of RM The denergizations of thevarious release magnets RM, RM and Ell I cause the restoration of thewipers of the various switches with which they are associated. When. theswitches have. reached normal as to their secondary movements, thesecoudarr ofilnormal' switches SOS-w, SOS w and S.().Sw are restored;when the wipers have been restored as to their. primary movements,

tacts (3, 7 and 8 of the called line, this line was a busy line. in suchcase, groundovill be connected to contact 6 and its multiples via theshifted test switch TSw, contact 110 of another connector (it the busyline be a 0 called line), or via armature 13 pertaining to the busyline, its contact 20, wiper 21 of a line selector then connectedthereto, to ground through contact 50 at the said line selector (if thebusy line he a calling line). 75

In either case, upon the energization of the test relay .Tlt at switchGr, as before described, the said relay, instead of being thereondeenergized, will have its armatures locked in their attracted positionsby cur- 8Q rent from grounded contact 6, wiper 105, normal contact 110,contact 104, right armature of relay TR, its right winding to battery.The testswitch contacts therefore remain at normal. and a busy signal istransmitted to the calling subscriber from interrupter I through theinduction coil and condenser, left armature of relay TR, normal contactof lower armature of relay 109, to

the left over the talking circuit indicated hy'90 heavy lines to switchE, via normal contact 70, condenser 83, to the left over the heavilymarked talking conductor, limb S of the line of A, through thetransmitter and the primary of the induction coil, causing an audiblesignal in thereceiver, returning over limh P, to the right overthe upperare still operatively connected to line limbs P and S rcspectivelyandthey are therefore, on the grounding of the line limbs, bothsimultaneously energized to close contact 84t-85. Circuit is thencompleted from ground at release magnetv'ltM of the line,

selector, contact 85,84, release magnet RM of the first selector tobattery. RM attracts its armature, closing circuit from ground atrelease uiagnet BM of second selector. F, through alternate contact ofprimary oil-normal switch 1.O.S'w contact 8(359, attracted armature ofRM- to battery. The attracted armature of RM closes circuit from groundthrough RM at the connector, normal. contact 122, the

shifted contact of primary off-normal switch ROS e0 contact Shh-93,attracted armature of RM to battery. I The armatures of all the releasemagnets are now attracted; and

when'gro'und is removed from) the two line "limbs at substation A, theresulting de'e'nergization of relays PR and SR allows contact 885 to beopened, deinerg'izing RM and Bhlflthe deenergiaation the latterdetinergizing Eli i the dctinergization of The calling sub- 100 RMdeenergizing HM; and each switch' is restored as its release magnet RM,RM, etc., isdeenergized. Thus it. is seen that until the calledsubscriber answers the call, the release of the connector remains underthe control of the calling subscriber; the instrumentality controlled bythe called subscribcr for removing the calling subscriber's control ofRM, consists of 122 of relay 118, which, when actuated, by disengagingits normal contact, opens a contact. in the circuit of RM and thereafterputs the. second busy )otential upon contact 99, as before described.

From the release operations already described, it is apparent that assoon as the line selector has selected his line, the calling subscribermay, by grounding. the two line limbs simultaneously, cause the closureof contact 85-84, which will be effective to release whatever switchesare connected to his line, so that, whatever stage of completing aconnection may have been reached, the release of all switches so far 0erated may be secured.

As before indicated, it may sometimes happen that a line selector willover-run on its primary or secondary movement through accident orcertain rarely occurring combinations of circumstances. To take care ofthese occurrences, I have provided the two switch springs 43 and 53; theformer being so related to the switch mechanism that, if the switchshall make an eleventh primary movement, the contact 43 will be closed;while if the switch makes an eleventh step in its secondary movement,the contact of 53 will be closed. In either case, a circuit will-becompleted from ground through the release magnet RM, contact 43 or 53,as the case may be alternate contact 47 of the rclease switch ES w tobatter energizing relcasemagno RM, upon whose energization the releaseswitch RSw will be shifted to normal, spring 47 then opening the circuitof release magnet RM, whose. deeucrgization causes the restoration ofthe line selector.

Referrin to armatures TSand 80 oil" switch E controlled by relay 76:their func- .tion to take care of certain dillicult ics which mightoccur were they omitted, being as follows: Assuming that the calledsubscriber has answered the call, causing the cnergiza- 'tion '01 relay76, then it will be remembered that current flows from ground at I). upper windings o'l relays Tat--75. attracted armature 50. attractedarmatlu'c 79, o\cr the talking circuit to limb $4. returning ovcr limbl.atlractcd armalurcs To and (12}. to battery through the lower windingsot relays T5 and 7-1. It is thus seen that the cir-- cuit energizingrelay T i i.- t|'accd through its own armaturcs 54' and (113 and thecalling line. Assuming that during conversation the calling subscriberaccidentally moves armature spring his dial Z from normal. the resultingopening of his linecircuit'. a t. contact. 4 would deenergize relay7;"); its ari'mltnrcs 5t) and (311 would tall back; and when the line atA wasagain closed condnctively, relay T5 wound continue deiinergized sothat when the subscriber replaced his receiver, ditt'ercntial releaserelay 74 would be out of openativ'c relation with his line. .-\rmaturecon-- tactsih and 80 are therefore. provided. controller l by relay Tti(which is only dciinergized when the release of the first. sclectoiactually occurs) establishing, when attracted, a parallel path forcurrent through the windings ot relays 74 and 75, thearmatures 56 and 63being excludedfrom this circuit so that an accidental opening of theline circuit at the substation of the calling subscriber, causingtemporarily the denergization of relay 75,v does not put the centraloflice apparatusin such condition as to prevent the said relay 75 frombecoming again energized when the substation circuit is again closed.

Referring now to the mechanical drawi ngs, as shown in Fig. a preferredform of the master-switch, the contacts 31 and 35 are the terminals ofthe line selectors, while the contacts 30 and 34 extend around under therespective rows of contacts 31 and 35 the wipers 30" and 34- (Figs. 2and 3) having in themselves no circuit connections, be"- ing employedonly to successively cross the individual contacts 31. and 3:") to therespective' common contacts 30 and 34-, leading (as shown in Fig. 1) tothe armatures of ,relays 29 and to relays 32. The said wipers 30 and 34are fastened 30 adapted to be driven, stcp-by-step, bythearmatiure-actuated pawl 30 of magnet 33, the magnet: being providedwith an interrupter actuated by its armaturi. as shown.

A line selector (Figs. +l, 7, 8 toll inclusive), comprises essentiallyten group con tacts 26 and a group wiper 27, making primarymovementsonly, a contact bank including one hundred sets of contacts 22,'20, 24, arranged in ten groups of ten sets of contacts each, a set ofwipers 23, 25, 21, capable of primary movements to select a group andsecondary movements in an intersecting plane to select ,a contact set ofa groupQa. primarv otl'-normal switch ROS)! comprising switch springsshifted on the first primary movement of the wipers, a secondaryoft-normal switch $0.82!) comprising switch springs shifted on the firstsecondary movement of the wipers, a release switch H.910 comprisingsprings shitted on the first primary movement of thcwipcrs, a prin'iaryover-run switch shifted when primary movement takes place and asecondary over-run switch shifted when a'ncleventh secondary movementtakes place. i

A sectional view of a. bank seen, from the to a rotatable ratchet aneleventl'i- 144 whose momentum is ell'ective, on the atbe caught andheld bv the hook of arm 13']. hen magnet RM is now dciincnqizcd, itsretracted armature draws arm i230 to the right, which. keeping its holdon delcnls l 125 and 12%. moves them away trom their shaft ratchcls sothat; the shafts are.now free to be restored. shaft SS by spring 231fastened to the wipers. and shaft PS by spring 161.

A spline .170 (Figs. l and 9) ishprovidcd on the secondary shaftengaging with tha first movementthereof any adjacent tooth ot ratchet124 to hold the primar sha'l't against return movmnent. to the end thaton I the restoration of the shafts as descrilicdf the secondary shaftmay be first completely restored clearing the wipers from thebank,whereon spline 170 releases the primary shaft and permits itsrestoration. 'lhe'ivri} mary and secondary cit-normal switches arc.- ofcourse restored by the. respective. shafts" when they reach normal. therestoration of the secondary one occurring first.

Recapitnlating the principal operations: the first actuation of primarymagnet PM rotates the wipers a step. shifts the primary elf-normalswitch. releases the primary and secondary shal'tdetents and shifts there-" lease switch. Subsequent actuations of said magnet serve only toadvance the wipers successive primary steps, until a possible. eleventhstep when the over-run switch is shifted. The first actuation ofsecondary magnet SM advances the line wipers a ondary step. shifts thesecondary oil-normal switch. and interlocks spline 170 with ratchet 124.Additional actuations of said magnet merely ad once. the line wipersadditional secondary steps until a possible eleventh step when thesecondary over-run switch will be, shifted. The'relcase magnet whenenergized shifts the release switch to normal, and when detinergizcdwithdraws the shaft detents, restoring the switch.

The mechanism associated with magnet '77 of Fig. 1, part .1. is shown indetail in the top view (Fig. 15). It includes the suitably pivotedteed-spool 14-5 carrying a supply of Inked ribbon 153-and record ribbon152 which may be of paper in alternate laytu s, and the receiving-spool140 to which lastcned ratchetv ll]. operated, to wind the ribbonsoll'thc teed-spool onto the rcccivingspool, by the pawl H52- l'astenedto arm lfit) upon armature 1 13, the attraction of said armature servingto draw pawl it.) to the left to engage the next tooth of ratch t 141.so that, on the retraction ol the. arn'iaturc, pawl 142 rotates ratchct1 l] and spool Ht) a. step. .-\r1nature 143 carries a hammer piecetraction of t lt), to give a reboundingblow upon the portions ot ribbons153 and 152 that :n'e'adjzu-entv to the hannner, prmtmg upon recordribljioi'i 155! whatever number upon the curved type trame o eration ofthe line elector, have been brought opposite the hammer 1'l-l-. The gene.l conformation of type frame 146 and its association with the primaryand secomlary'shatts will be seen in Fig. 15 and Figs. ll. ll) and 11.The cylindrical bearing ol. .t'ranu: 'l-lti is splined to primary shaftPS (a shown in Fig. 1:1) so that. it is rotated with lhesha'tt, but istree to move down and up thereon. The lower edge of the frame Ill; ispressed agail'ist a projection .1119 on secondary shaft SS (Fig. spring11-? shown in Figs. 1), l0, and 11. to the end that. when shaft SS isworked downwardly in the operation of the line so. lcctor, spring H9 maymove. the type frame 1 H] a corresponding cxlent downward.

The type numbers corresponding to the respective tens and units valuesol the subscribers lines in their respective hundreds arc to securegreater spacing, preferably arranged in ten vertically disposed doublecol-- nmns. as indicated in .l igs. 10 and ll, numbers 11, 12. 13. H.etc, comprising a double column.

sllll]il1; that subscriber 9924. makes a. call. the primary shaft. ll'iof the line solector Fig. t. makes of comr'se two rotary steps whichbring the column of numbers including g1, 22, 23. etc, to a positiondirectly above the hammer end 151, (Fig. 15). The. secondary shaft HQthen makes four downward steps to bringthe wipers to connectv with thecontacts ol the line, and spring 1 17 causes the type -l'rame to descendcorrespondingly. number Z-l being thereby brought di rectly opposite thecnd 151 of hammer .144. Similarly, it" any other subscriber makes acall, the line selector o 'ierating will, with the zuljustment of itswipers. move its type frame so that the type number correspond ing tothe number of the. calling line 1s adjusted to the hammer. \Vhen a'lineselector is restored its shafts of course restore the type frame tonormal.

'lelcphone subscribers on measured service are usually'cl'iargod onlyfor such calls as are answered, and to conform to this practice. l haveso arranged the circuits of my svstcm that printing magnet 77 is onlyoperalcd in case aml at. the moment when the called subscriber responds..\t that time it will of course record the number of the callingsubscriber on ribbon 152. hen the 146 may, by the calling subscriber at.the end oi".conversationcauscs the first selector to be restored, mag-.

net 77 is detincrgized and pawl 142, turning spool 14-0, ln'ings freshspaces of ribbon in front of hannner and 151 ready to print; the nextnumber. Since, the line selectors belong to a particular one hundredlines, it is necessary, in order to get a pernianent printed record ofeach completed call over a line, to place upon the type frames of theten line 1:3) by a spiral selectors only the last two digits of eachsubscribers number, the line selector itself indicating the thousandsand hundreds digit.

It is apparent that only one thousand call recorders are required torten thousand subscribers lines, a material. saving' over recordersindividual to lines.

The mccluinisni of the first, selector is, in general, similar to thatof the line selector. The vibratory interrupter of the primary magnetand the measured service mechanism are omitted.

The primary oiT-normal, secondary oil normal and release switches arecontrolled in a nianner similar to'those of the line sclector, and theadjustment of the line wipers is mechanically similar, The springcombinations of the various off-normal and lease switches corrcs 'mlnlof: course to those indicated at E in i.

In Figs. 5 and (3 shown the nicchanisn'i associated with the firstHElrAjlGl' for shifting Sp]; 5 7i, and Ti, 32, dime-Flinn. in (:-f)l'inectlon with .lig. l; springs mounted as indicated in Pig. o, the viedslimving the springs at normal. The two insulated studs .135) are drawnto the left to shift the springs, and when they are freed the tension ofthe springs rot-ores the studs and springs. The studs 12-35 are fastenedto an arm 134 (Fig. (5) pivoted as shown, and having a small projectionon its lower e trcniity adapted to he engaged by the hook of arm 133when the arn'zaturc of magnet 73 is attracted. i lhen said magnet isthere; er deener ized on the response of the called subscriier, itsretracted armature causes 133 to draw the lower portion oi. nie'i'nher134 to the right, whereby studs move to the leftto shift their snrings.

The operation of release magnet RM is similar to that of magnet RM ofthe line selector, except that its armature carries an arm 136 adapted,when the armature at ti'acted, to en 'ag e and lift hooked arm 133 freeof mem 1' 134, thus allowing the restoration of studs 135.

It will .be reinemhere'd that the shifting of spring 72 (see Fig. 1)energizes relay 76, whose energization causes-that of theprintinfigmagnet 77. The latter should preferab y not be operated whena. calling snh-- scriher has connected his line with. an idle calledline and fails to secure an answer. Under such circumstances, magnet 73is ener gized as soon as connection is madc wit-h the called line, andits denergization follows when the calling subscriber replaces his 1"-ceiver, causing the energization of releas maiet RM, which, by shiftingspring 1h. 24;, energised relay BR whose armatnre opens tie circuit ofmagnet 73. The previous encrgization of 73 has,cau sed arm 133 to engagemember 1.34 (see Fig 6) The energization of magnet RM, preceding thedeenergization of magnet 73, is effective lo cause arm 1.36 to lift arm133 free that the deenergization of magnet 73 (oc curing while magnet RMremains energiZ-cd) is inetl'ective to move n'ielnher 134; spring 72 andthe other associated springs remaining at normal, \i'hsri'el'iy animproper I)(J&lll )ll o'l magnet 77 is avoided.

The second selector is mechanically similar to the first selector,except that .n'iagnct 73 is not employed, the various ofi norinal andrelease spring con'ihinations being a1." ranged as indicated at F inFig. 1.

The connector shown in Figs. 12, 13, 14 inclusive, is generally similarto the first selector. No vibratory circuit-breaker of the secondmymagnet SM is provided and the positions of the Wipers with respect tothe contact bank is such that two secondary steps are required tocausethe Wipers to engagc the first contact set of a selected rovv for thepurposes hcreinhefore indicated.

'ihe niechanis ,1 of test relay TB is best shown. in Fig. 1 1-. The testswitch sprin lid-ill are preferably vertically disposed and am; 1.37,carried by the arn'iatnre of relay TR, has a raised portion adapted,when the armature is attracted, to clear spring 111, the springassociated with arm then missing the upraise'to engage said spring 111.Uri the deenergization of relay TR, the springs 111i. and 210 are ofcourse shifted for the purposes hereinhefore in? by arm 13.: dicated.When release magnet attracts its armature, piece 138 fastened theretodraws arm 13? down so that its upraise frees spring 11.1 and thetwosprings 11 0, 111 by their tension return to i'iorinal. .Moreover itwill he -h served that when testrelay TR is locked because the switchwipers have engaged terminals of a has} line, the energization of therelease magnet. 3M (occuring when the calling subscriber replaces hisreceiver) will be eilfective by piece 138 to Withdraw arm 137 fromengagement with sgring 111} so that the springs remain 1111-- s ifted,It is to be. u'ndestood that Fig. 1, purely symholical diagram, thevarious isa cated by conventional signs, no attempt hecon doctors,relays, anhatnres, etc being indiing made to indicate mechanicalstructures therein or particular types of apparatus, as those skilled inthe art will readily supply the mechanisms best adapted for practicingthe invention. Similarly, any known or approved mechanical combinationsmay he employed in place of the particular con'ihinations 1 have electedto illustrate in the me chanical' drawings, and I do not. intend tolimit. my invention to switches having movementsin intersecting planes.The various batteries illustrated at B, B and B may, if desired, he asingle battery.

It is my intention not to limit the scope

